Nickel (Ni), a widely used metal in a variety of industries, is a well documented carcinogen as well as a potent skin sensitizer causing severe allergic contact dermatitis. Thus, the causal role of Ni compounds as occupational hazards is significant. Cytoskeletal perturbations and alterations have been associated with cell transformation as well as a number of human pathological conditions. Furthermore, previous studies from this laboratory have shown that several heavy metals including Ni can induce dramatic microtubule (MT) alterations in mouse 3T3 cells. Moreover, dramatic nucleotide pool imbalance, which can influence the fidelity of DNA synthesis, has been observed following cytoskeletal injury. Thus, it is reasonable to expect that cytoskeletal perturbation may have a crucial role in mediating Ni-induced cellular toxicity and carcinogenesis. The specific aims of this proposal are: 1) to investigate the role of microtubule-associated proteins (MAPs) in mediating the Ni-induced MT perturbations via two-dimensional gel electrophoresis; 2) to determine the effect of Ni on tubulin polymerization using an in vitro, purified bovine brain tubulin model; 3) to examine the redistribution of cytoplasmic organelles following the Ni-induced cytoskeletal disturbance via fluorescent probes; and 4) to investigate the changes in cellular nucleotide pools via HPLC analysis following Ni-induced insults. Results from this research may lead to a better understanding of the molecular mechanisms of Ni-induced cellular toxicity and other perturbations as well as the role of cytoskeleton in mediating cellular injuries in other disease processes.